Apparatus for contour forming



Jan. 31, 1961 T. w. HowLETT, JR., ET AL 2,969,758

APPARATUS FOR CONTOUR FORMING Filed March 5, 1957 INVIORS.

U VIVLILILIIIHl.

Jan. 3l, 1961 T. w. HOWLETT, JR., ETAL 2,959,758

APPARATUS FOR CONTOUR FORMING Filed March 5, 1957 2 Sheets-Sheet 2United States Patent 2,969,758 APPARATUS FOR CONTOUR FORMING Thomas W.Howlett, Jr., Hammond, and Amel R. Meyer, Griffith, Ind., assignors, bymesne assignments, to Union Tank Car Company, Chicago, lll., alcorporation of New Jersey Filed Mar. 5, 1957, Ser. No. 644,156

1 Claim. (Cl. 11S-44) The invention relates to a novel apparatus havingparticular utility in forming to desired contours various materials suchas metallic plates.

In many industries, such as for example, the plate fabricating industry,it is frequently necessary to form materials into pre-determinedcontours. The particular shapes desired have presented the persons inthe art with many problems from the standpoint of forming the material,especially in an economical and satisfactory manner. A typicalillustration relates to manufacturer of tank equipment of various typesof metals such as steel, aluminum, etc. The tanks may be of generallycylindrical form and provided with dished heads at opposite ends of thecentral cylinder. Little problem is encountered in forming the centralcylindrical portion as a flat plate of desired material need merely berolled into cylindrical form, thereafter having its abutting endsappropriately secured in any conventional manner such as by welding.More diiliculty is presented in forming the dished or contoured heads toclose the ends of the cylinder and here the conventional methods of dieforming in a mechanical or hydraulic press or spin forming to contourhave frequently been utilized to accomplish the desired end.

The economy of manufacture of these dished heads has been subject tofrequent scrutiny because expensive die or mandrel equipment must lbeprovided which becomes excessively costly from the standpoint of unitproduction where low volume head production is required. In point offact, such low volumeY and high unit cost does occur frequently becausetanks of this nature are fabricated to customers specifications whichdictate variety in important details in most instances. To summarize, insuch low volume production the high cost of die or mandrel equipment aswell as the considerable expenditure in capital machinery such aspresses or spinning machines has rendered such manufacture extremelyexpensive.

Accordingly, it is a primary object of the invention to provide anarrangement olering a comparatively inexpensive method and apparatus forforming to determined contours.

It is a further specific object of the invention to provide a novelphysical arrangement which utilizes the force available as a result ofdetonation of high explosives to directly act upon and form metals todesired shapes.

Specifically, one embodiment of the invention contemplates the use, incombination, of a comparatively inexpensive die arrangement, a metallicplate to be formed, the adjacent location of a determined quantity ofhighly explosive material, a lluid ballast to accommodate reactive andconductive means for the explosive force, and a determined physicalarrangement of the mentioned structure to utilize the force resultingfrom an explosion of the material to accommodate desired plateformation.

lt has been found that this type of arrangement quickly and easily, forexample, forms llat plate material into desired contours and has aparticular advantage over earlier prior art methods in that the tendencyto unde- 2,969,758 Patented Jan. 371, 1961 sirably mar the surface ofthe material as the result of mechanical action thereon is greatlyreduced.

The invention is best illustrated with reference to the followingspecification and to the associated drawings wherein:

Figure 1 is a partially schematic, sectional, side ele-V of any suitableconfiguration and for illustrative purposes is seen to comprise aplurality of sand bags 4 appropriately mounted on a concretev or firmfoundation 6. A containing liner of flexible and liquid imperviousmaterial 8 is positioned over the sandbags 4 whereby the entirearrangement may accommodate a head of water 10 without leakage.Centrally of the vessel 2, a die arrangement, indicated generally at 12,may be located. A supporting bracket 14 having a center bar 16 isarranged above the die 12 to position and support an explosive charge 18in determined relation to the die arrangement 12. A passage or line 20may be provided in the concrete foundation 6 and establishescommunication with Vthe atmosphere as at 22 while having itsv other endcommunicating with the die arrangement 12 as at 24 (Figure 2).

Directing attention to Figure 2, it will be seen that the diearrangement 12 may comprise an annular supporting member 26 carrying, atthe upper edge thereof, a piece supporting ring 28. Centrally of thearrangement 12 a die .insert 30 is provided, said die insert preferablybeing of non-metallic material such as hardwood which is one of theeconomical features of the disclosed invention. A piece of rigidmaterial such as a plate 32 may be positioned in engagement with theupper surface of the ring as at 34 prior to forming. A clamping member36 is provided to engage the upper surface of the plate 32 adjacent itsperipheral edge. A plurality of clamping bolts V38, extending between aperipheral ledge 40 and the plate 36, serve to fixedly maintain or clampthe plate 32 to the ring 28.

The pipe 20 is connected to and communicates with a base plate 42, saidplate 42 engaging upstanding llanges 44 which inv turn form part of abaille plate 46, said baffle plate being arranged, in the illustratedembodiment, to engage the bottom surface of the insert 30 as at 48.

Brielly referring to Figures 3 and 4, it will be noted that the insert30 and the baille plate 46 are provided with a plurality of apertures 50and 52 respectively. In the assembled condition the apertures 52 of thebaille plate are preferably arranged to register with the apertures ofthe insert 30, the purpose of which will hereinafter be explained indetail. Sutlice it now to say that the apertures 50 communicate with thedie cavity 56 defined by the upper surface of the insert 30 and thelower surface of the mounted plate 32. This arrangement in combinationwith the upstanding flange construction of the baille plate 46 thusestablishes a line of communication between the die cavity 56 and theatmosphere via pipe 20.

In an illustrative operation of the herein disclosed method and,apparatus, it will be noted that the die arrangement 12 may bepositioned in the containing vessel 2 so that the mentionedcommunication is established between the cavity 56 and the atmosphere.Thereafter, a plate 32 may -be positioned on the ring member 28 andclamped thereto so as to be in substantial sealing engagement with thedie arrangement 12. If desired, the ring 28, the plate 32, and/ or theclamping member 36 may be lubricated with a suitable grease or the likeso as to assure a substantially liqfuid tight connection between theparts mentioned. Thereafter, a head of liquid 10 is provided in thevessel 2 so that ythe explosive charge 18v as well as the upper surfaceof the plate 32 are immersed therein. It will 'be noted that because ofthe fact the plate 32 is in liquid tight engagement with the die 12 thatan arrangement has been provided wherein .fluids of 'substantiallydifferent density are provided on opposite sides of the plate 32,namely, water on .the upper surface of the die and air in the cavity 56.Y

f course, it will be understood by those skilled in the art, that -theexplosive charge 18 is connected to suitable detonating equipment (notshown). The high explosive charge 18 may then be detonated and theexplosive force thereof is transmitted downwardly through thesurrounding water and impinges itself on .the upper sur-face of theplate 32 forcing the latter downwardly into the die arrangement 12 andparticularly into initirnate contact therewith as is illustrated inphantom lines at 62 in Figure 2.

The presence of the less dense fluid or air in the cavity 56 coupledwith the communication established between said cavity and theatmosphere readily accommodates the evacuation of said less dense uidsubstantially simultaneously with the detonation of the charge 18thereby allowing forcible movement o-f the plate 3-2 into intimatecontact with the die member 12.

Lt will be noted that in lthe illustrative embodiment, the explosivecharge 18 is positioned centrally above the plate 32 and die arrangement12. '111e exact location of the explosive charge as well as the depth ofthe water or liquid -head 10 will vary depending upon the type ofmaterial used and the configuration of the product to be formed. Also,in some instances, it may be desirable to form the particular materialin stages with a plurality of explosive forming steps in sequence.

Another advantage to the method and apparatus disclosed relates to thecondition of the plate 32. The action herein described does not severelymar or indent the surface of the plate 32, as has frequently been thecase in more cnoventional methods of forming such as on press equipmentor spin forming to a mandrel. [[t has also Ibeen found that .the methodand apparatus here described has particular utility in forming die headsof various contours in low quantity production set ups in view of thefact that the explosive charge utilized is relatively cheap and that dieinserts may be made of relatively cheap and easily formed non-metallicmaterial such as hardwood thereby considerably reducing theI cost of lowquantity production items.Y Further, the investment in capital equipmentis substantially reduced as compared to the prior methods of formingheretofore considered.

The invention as shown is by way of illustration and not limitation andmay be subject Ito various modifications without departing from thespirit thereof or vthe scope of the appended claim.

What is claimed i's:

In an apparatus of the .type including a vessel containing a liquid, anenergy producing device located in the liquid for forming a normallyrigid material, supporting means for s aid'rigid material, die means'spaced from said rigid material and including means defining aplurality of openings extending Ibetween opposite sides of 'the diemeans, baie plate means detachably secured to the side of said die meansremote from the rigid material and including means defining a pluralityof openings in registry with said die means openings, 'passage meansestablishing communcation between a point in the bottom of the vesseland the atmosphere, and said plate means including a plurality ofgbfaies extending radially oi said point and a central area of the diemeans and in engagement with the bottom of said vessel to providecommunication vbetween saidregistered opening means and said passagemeans to facilitate evacuation of air betweenv the rigid-material and,the die means during a forming operation.

References Cited in the Y'tile of this patent UNITED STATES PATENTS669,279 Harrington Mar. 5, 1901 2,038,304 Middler Apr. 2l, 19362,348,921 Pavlecka May 16, 1944 2,648,125 McKenna et al Aug. l1, 19532,669,209 Hoffman Feb. 16, 1954 2,728,317 Clevenger et al. Dec. 27, 19552,781,016 Livermont Feb. 12, 1957 2,849,977 Nielsen et al. Sept. 2, 1958FOREIGN PATENTS 105,422 Sweden. Sept. 8, 1942 657,727 Great BritainSept. 26, 1951

